1. Field of the Invention
The present invention relates to an image-reading apparatus, an image-reading method, and a program.
2. Description of the Related Art
Heretofore, technologies of image-reading apparatus have been developed to automatically detect the tilt and position of a document and to clip only the document area.
For example, there is a method to improve the accuracy with which the document area is detected, where the linearity of the edge of a document is detected so that the effect of the edge that is different from the end of the document is reduced (see JP-A-2007-088654).
Furthermore, there is a method to improve the accuracy with which the tilt of a document is detected, where the two sides that are perpendicular to each other or the two sides that are parallel to each other are selected from the edge of a document, and the tilt of the document is detected (see JP-A-2009-267652).
However, conventional methods for detecting a document area have a problem in that it is difficult to handle various types of document and shapes of a document, such as a document of a medium that is stitched and cut out. Specifically, the cut side of a document is sometimes tilted compared with a group of other straight lines, or a distortion occurs on a document due to the manner of feeding it during reading; however, according to conventional methods for detecting the document area, it is difficult to detect the tilt and position of a document with a high accuracy.